Patent GB-648531-A (GB)
Title: Improvements in or relating to variable speed transmission mechanisms for automotivevehicles
IPC: F16H61/02
Filed: 1946-02-26
Abstract: 648,531. Controlling hydromechanical variable-speed gearing. BORG-WARNER CORPORATION. Feb. 26, 1946, No. 5957. Convention date, Feb. 26, 1944. [Class 80(ii)] In a motor vehicle variable-speed gear in which overriding downshift from a high to a low speed ratio is ejected by accelerator depression to a " kickdown " position in which the vehicle engine throttle is fully open, means are provided, under the joint control of a vehicle service brake and a governor responsive to the speed of the gear output shaft, to neutralize the gear when the brake.is applied and'the output shaft is rotating below a predetermined speed thereof. Additionally, the governor may be effective normally to downshift the gear below this predetermined speed and to upshift the gear above a higher predetermined output shaft speed. In both described embodiments, the accelerator has "kickdown" and "neutral" positions beyond the normal "open" and "closed" positions corresponding to the limits of its throttle-operating range, full accelerator release subsequent to kickdown upshifting the gear at any output shaft speed in the form without additional governor control, but only above governor upshift speed in the form with such control. As shown, the impeller 18, Fig. 1, and turbine 20 of a hydraulic torque converter are rigid with the reaction sun 16 and driven planet carrier 17 of an interengaging-planet epicyclic gear whose driving annulus 12 is powered from an input shaft 10. Power passes from the carrier 17 via hydraulicallyoperated alternative, and preferably cone-type, friction clutches 28, 30 to an output shaft 11, either directly or through a second interengaging-planet epicyclic gear having a driving planet-carrier 37, a driven annulus 33 and a planet-carrier 34. Hydraulically - operated alternative brakes 26, 21 are provided, the first, when engaged, stationing the sun 34 and, through a one-way clutch 24, holding the converter reaction member 23 against backward rotation to give high or low forward speed ranges through the clutches 28, 30 respectively; and the second, when engaged, stationing the carrier 17 and turbine 20 to give a reverse drive through the reaction member 23 and sun 34, the clutch 30 being also engaged to station the carrier 37. Actuating oil for the clutches and brakes is provided from a tank 40, Fig. 2, replenished from the transmission sump 75 by a pump 74. A second pump 41 supplies, through ports 50 and 57, 59 respectively, a brake control valve 42, preferably mounted on the vehicle steering column, and a clutch control valve 56, a relief valve 43 being provided having two spring loaded valve members 44, 45 the first of which ensures an adequate pressure at the valves 42, 56 and the second of which provides a conduit 76 with the pressure oil for lubricating purposes. A manually operated member 52 is slidable in the valve 42 to close the port 50 as shown for neutral, or to connect it alternatively to ports 49, 51 supplying the forward and reverse brakes 26, 21 respectively. The ports 57, 59 supply, through ports 58, 60 respectively, the high and low forward speed clutches 28, 30 upon energization of high and low speed solenoids 70, 72 actuating valve members 62, 66 normally spring-urged to cut off the supply to the clutches. The brakes and clutches discharge to, the tank 40 on disengagement through ports 48, 61 respectively. Combined manual and automatic electrical control means for the solenoids 70, 72 are provided. A relay winding 82, Fig. 3, in circuit with a battery 80, is energized by closing the vehicle ignition switch 81 and closes a switch 84 supplying voltage to relay windings 86, 88, 90, 93, 96 and 98. These relay windings are interconnected, as shown in Fig. 3, with each other, and with a further relay winding 116 and with the solenoids 70, 72, by relay contacts 91, 94, 100, 104, 105, 107, 108, 114, 117 and 123, by holding coils 115 and 121 and by switches 102, 109, 122 and 124 actuated manually or automatically as follows. The switch 102, manually operated simultaneously with the valve 42, and also preferably mounted on the vehicle steering column can move from a central neutral position to bridge forward or reverse drive contacts 103, 106 respectively. The vehicle accelerator 110 controls the switch 109 which has contacts 111, 112 and 113 so arranged that depression of the accelerator from its "neutral" position D to its "closed" position E bridges the contacts 111, 112 and further depression of the accelerator through its "open" position F to its "kickdown" position G bridges the contacts 113 also. The switch 122 is closed when the vehicle service brake is applied, and the switch 124 is closed above a predetermined vehicle speed by a govenor 125 powered from the output shaft 11. With the ignition switch 81 open, the circuit is in the condition shown in Fig. 3. After closing of the switch 81, bridging of the forward drive contacts 103 energizes the winding 88 and closes the associated contacts 104, 105. Movement of the accelerator 110 from its "neutral" to its "closed" position then energizes the winding 116, closing and opening respectively the associated contacts 100, 117 and energizing the high speed solenoid 70, which, due to the holding coil 115, remains energized despite subsequent opening of the contacts 112. Depression of the accelerator through its "open" position to its "kickdown" position, however, energizes the winding 90, opening the associated contacts 91 and reenergizing the winding 116 to break the circuit of the solenoid 70. The winding 93 is at this time energized through the contact 112, closing the associated contacts 94 and energizing the low speed solenoid 72 through the closed contacts 117 of the deenergized winding 116. The solenoid 72 remains energized during subsequent movement of the accelerator between its "open" and "closed" positions so long as the holding coil 121 remains energized through the contacts 111. Movement of the accelerator to its "neutral" position opens the contacts 111 and de-energizes the winding 90, allowing the contacts 91 to close. The consequent current through the winding 116 is, however, limited by the coil 115 and is insufficient to bring in the high speed solenoid 70, the low speed solenoid 72 remaining energized by the energization of winding 93 through contacts 104, coil 115 and contacts 114 until the accelerator is again moved to its "closed" position to bring 'in the solenoid 70. Bridging of the reverse drive contacts 106 energizes the winding 96, opening and closing respectively the associated contacts 107 and 108. energization of the high speed solenoid 70 is thus prevented, and the winding 93 is energized when the contacts 112 are bridged, allowing the low speed solenoid 72 to become energized through the contacts 94 and 117. With the vehicle moving below the predetermined governor speed, the switch 124 is open de-energizing the winding 86 and closing the associated switch 123. Application of the vehicle service brake under these conditions closes the switch 122 and energizes the winding 98, opening the associated contacts 114 to de-energize the windings 93 or 116 and thus whichever of the solenoids 70, 72 is engaged, and neutralizing the transmission. When the vehicle is moving above governor speed the switch 123 is held open and closing of the switch 122 has no effect. In a modified electrical control means for the solenoids 70, 72, the governor 132, Fig. 4. includes additional contacts 131 which close at a higher vehicle speed than the contacts 124 (e.g. twenty m.p.h. and five m.p.h. respectively) and are in series with a relay winding 129 and a switch 127 closed when the winding 86 is energized. Contacts 130. closed when the winding 129 is energized, are in series with the contacts 91 which are now disconnected from the winding 116 and connected to the contacts 105, these latter being disconnected from the contacts 104 as shown in Fig. 4, on closing switch 84 voltage is now supplied to winding 116 also. Once closed, the contacts 130 are maintained so by a holding coil 133 until the vehicle speed falls sufficiently to open the switch 127 via the switch 124. Initial depression of the accelerator 110 now energizes the winding 93 through the contacts 104, 112 and 114, and closes the contacts 94 to energize the low speed solenoid 72. Subsequent closing of the contacts 130 energizes the winding 116 through contacts 105 and 91, and so cuts out the solenoid 72 and energizes the high speed solenoid 70, which remains engaged unless the vehicle speed falls sufficiently to open the switch 124 or the accelerator is depressed to its "kickdown" position. Provided that the high speed ratio is operative, such accelerator depression acts as before to change to the low speed ratio which is then similarly maintained by the coils 121, 115 until the accelerator is released to " neutral " position and subsequently depressed to "closed" position; when, if the vehicle speed is sufficient for closure of the contacts 131, the high speed ratio will be again engaged. The solenoids 70, 72 have operating and holding coils, the former being cut out after operating by armatureactuated switches 119, 119<SP>1</SP>.